A sucker rod has an elongated metal body with threaded couplings at each end. The sucker rods are connected end to end to form a rod string to operate a pump positioned down a well. When there is a failure in the rod string, it can usually be attributed a failure occurring at one of the threaded couplings. In order to avoid such failures, the threaded couplings are being made considerably stronger than the body of the sucker rods. Notwithstanding that the threaded couplings are stronger, failures of the rod string are still occurring at the threaded coupling.